Optical slit apparatus



MarchZG, 1968 s. H. o'r'r, SR 3,374,705

OPTICAL SLII APPARATUS Filed on. 23, 1965 I INVENTOR.

m GEaRGE H. OTL'JR. O N BY ArrakNE-Kr United States Patent 3,374,705 OPTICAL SLIT APPARATUS George H. Ott, Sr., St. Paul, Minn., assignor to Fabri- Tek Incorporated, Minneapolis, Minn., a corporation of Wisconsin Filed Oct. 23, 1965, Ser. No. 503,935 9 Claims. (Cl. 88-24) This invention is concerned with production apparatus, and more particularly with an adiustable optical slit device.

The apparatus of this invention will find many uses in the optical production or drafting of lines. It is particularly useful in the production of patterns for etching printed drive-lines and film-memory bit arrays for use in magnetic memories. The advantages of the subsequently described invention will be apparent to those skilled in the art, who realize the minute dimensions and rigid tolerances used in such memory arrays. Production of patterns for such arrays has previously necessitated that a master layout, up to ten times actual size, be taped up by a draftsman, then photographically reduced to a desired size.

In addition to the considerable time and cost involved in the tape-up process certain inaccuracies arise from this method of photographic reduction, such as lens distortion which may cause edges of the pattern to assume a barrel shape rather than be perfectly straight, and a tilting type of distortion caused by any lack of parallelism among the pattern, lens, or the exposed plate.

The apparatus of this invention provides the advantage of producing a 1:1 pattern of lines directly onto the photographic plate. This completely eliminates the tape-up and the photographic reduction processes along with the time and cost involved in these processes. Also, inaccuracies resulting from the photographic reduction method are eliminated.

in the drawings:

FIG. 1 is a perspective view of an embodiment of this invention; and

FIG. 2 is a top plan view of a portion of the embodiment shown in FIG. 1.

Referring now to FIG. 1 there is disclosed an adjustable optical slit apparatus indicated generally at 10. There is also shown a top plate 11 having a plurality of slots 12, 13 and 14 cut in one end thereof for mounting of apparatuse to a holder. A pair of parallel legs 16 and 17 extend outwardly from plate 11.

A block 22 has one end mounted to th; underside of leg 16 by a pair of fastening means here shown as bolts 24. Another block 23 has one end connected to the underside of leg 17 by fastening means here shown as a pair of bolts 25. Connected between the other ends of blocks 22 and 23 is a strip 30 having a tapered edge 31.

A block 32 has one end connected through a slot 18 in leg 16 by fastening means or bolt 34. Another block 33 has one end connected through a slot 19 in leg 17 by fastening means or bolt 35. Connected between the other ends of blocks 32 and 33 is a strip 40 having a tapered edge 41 adjacent to edge 31 for defining optical slits. Block 32 has an aperture or hole 38 cut therethrough for receiving a precision adjustment device 42 here shown as a micrometer. A slot 36 cut between hole 38 and the edge of block 32, in combination with a bolt 28, serves as means for locking micrometer 42 into hole 38. Block 33 has a hole 39 cut therethrough for receiving another precision adjustment device 43, also here shown as a micrometer. A slot 37 and bolt 29 are used to provide locking of micrometer 43 in hole 39 in the same manner as slot 36 and bolt 28 of block 32. There is also shown a bar 57 which has one end rigidly connected to strip 30 by a bolt or rivet 58, and another end, containing a slot 60, connected to strip 40 by a spring loaded bolt 59 which passes 3,374,705 Patented Mar. 26, 1968 "ice through slot 60 and is threaded into strip 40. Another bar 61 has one end rigidly connected to strip 30 by a bolt or rivet 62, and another end, containing a slot 64, connected to strip 40 by a spring loaded bolt 63 which passes through slot 64 and is threaded into strip 40.

A mount 52 is connected to one end of strip 30, and a mount 53 is connected to one end of strip 40. A spring 54 is connected between mounts 52 and 53 to yieldingly bias tapered edge 41 toward tapered edge 31. Another set of mounts and spring similar to mounts 52 and 53 and spring 54 is attached between the other ends of strips 30 and 40, not visible in this perspective view of FIG. 1. Through a cut away portion of leg 17 of plate 11 there is shown a movable arm 45 of micrometer 43. Arm 45 is here shown pressing against a shim 47 placed between arm 45 and block 23.

FIG. 2 is a top view of the lower left portion of the apparatus 10 of FIG. 1, with top plate 11 removed. In this view, it can more clearly be seen how micrometer 43 extends into aperture 39 where it is grasped for mounting on block 33. In this drawing arm 45 is shown pressing directly against block 23, without the use of shim 47 as shown in FIG. 1.

In operation, the adjustable optical slit apparatus 10 can be used in combination with a source of light and a photographic plate. Apparatus 10 is first mounted by means of slots 12, 13 and 14 in plate 11 to a stationary holder. A photographic plate is placed on a table under apparatus 10, after which the holder is adjusted so that apparatus 10 lies flat on the photographic plate. A light source is then made available above apparatus 10 to shine through the linear aperture or slit formed by tapered edges 31 and 41, to expose a precision shaped segment of the photographic plate. A collimated light source may be used, and if so apparatus 10 may be stationed slightly above the photographic plate is desired.

The rigid connection of blocks 22 and 23 to plate 11 will serve to hold strip 30 stationary. Inasmuch as blocks 32 and 33 are mounted in slots 18 and 19, respectively, and bars 57 and 61 are connected to strip 40 by bolts 59 and 63 which extend through slots 60 and 64, respectively, strip 40 is free to slide to move tapered edge 41 toward and from tapered edge 31. Springs 54 mounted between strips 30 and 40 at each end thereof tend to bias edge 41 toward edge 31. The dimensions of the aperture between edges 31 and 41 may be precisely set with micrometers 42 and 43, by varying the pressure of arm 45 against plate 23, and the pressure of a similar arm (not shown) of micrometer 42 against plate 22. The slit thus defined by tapered edges 31 and 41 may be precisely made parallel or tapering.

If desired, once a calibrated setting has been achieved, variances in the slit can be made by inserting shims such as shim 47 between the arms such as arm 45 of micrometers 42 and 43, and the blocks 22 and 23. Variances in the slit can also be made by utilizing the scales of micrometers 42 and 43.

To complete a pattern on the photographic plate, a change in position of the slit during the exposure cycle can be accomplished by having the photographic plates on a table which can be moved by its own precision control. The photographic plates may be held tightly against strips 30 and 40 by clamping apparatus 10 securely to the table on which the photographic plate is held. In another embodiment of this invention a series of parallel holes are formed in each of strips 30 and 40 and connected to a common vacuum manifold which draws the photographic plate firmly against strips 30 and 40. In yet another embodiment of this invention strips 30 and 40 are magnetized to attract a magnetizable surface contiguous with the photographic plate to hold it firmly against strips 30 and 40.

In addition to the above described method for laying out parallel or tapered lines on a fiat photographic plate, the same general approach can be used for making precision shaped lines on a variety of ditferently shaped objects and materials.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as fol lows:

1. Adjustable optical slit apparatus comprising:

a first strip having a slit defining edge;

means connected to said first strip for stationary mounting thereof;

a second strip having a slit defining edge;

means coupling said strips and adapted to allow linear slidable motion of said first strip with respect to said second strip, said slit defining edges being in adjacent relationship;

means connected to said strips yieldingly biasing said second strip toward said first strip;

a first pair of blocks mounted one on each end of said first strip; and

a second pair of blocks mounted on said second strip each opposite one of said first pair of blocks, each of said second pair of blocks having mounted thereon precision adjustment means adapted to contact the opposite one of said first blocks for precision adjustment of the slit defined by said edges.

2. The apparatus of claim 1 in which said slit defining edges comprise tapered edges.

3. The apparatus of claim 1 in which said means coupling said strips comprises a pair of bars having one end rigidly connected to said first strip and another end slotted; said other end connected to said second strip by a spring loaded bolt inserted through said slot into a threaded hole in said second strip.

4. The apparatus of claim 1 in which said means connected to said strips yieldingly biasing said second strip toward said first strip comprises a pair of springs, one connected between said strips at each end thereof.

5. The apparatus of claim 1 in which said precision adjustment means comprise micrometers.

6. The apparatus of claim 1 including a plurality of apertures formed in said strips and adapted to be connected to a vacuum source tor holding ,mat rigl to be worked against said strips.

7. The apparatus of claim 1 in which said strips are magpetized. for holding magnetizable material to be Wked against said strips.

8. In apparatus for the control of the dimensions of a slit, the combination comprising:

a mounting plate having a first leg extending in a first direction including means for mounting said plate to a holder, and second and third parallel legs extending opposite to said first leg;

a first pair of blocks one mounted in each of said second and third legs and extending downwardly at substantially right angles thereto;

a first strip mounted to said first pair of blocks in a plane substantially perpendicular thereto;

a slot in each of said second and third legs;

a second pair of blocks one slidably mounted in each of said slots opposite one of said first pair of blocks and extending downwardly substantially parallel thereto;

a second strip mounted to said second pair of blocks adjacent to and lying in the same plane as said first strip, the adjacent edges of said strips being tapered for defining slits;

a pair of bars having one end connected to said first strip and another end slotted, said another end being connected to said second strip by a spring loaded bolt passed through said slot and threaded to said second strip;

a pair of springs mounted between said strips one at each end thereof, for biasing said second strip toward said first strip; and

precision adjustment means mounted in each of said second pair of blocks and adapted to cooperate with the opposite one of said first pair of blocks to adjust 1:16 width and taper of the slit between said tapered e ges.

9. The combination of claim 8 in which said precision adjustment means comprise a pair of micrometers.

References Cited UNITED STATES PATENTS 2,964,998 12/ 1960 Middlestadt 350-271 2,971,431 2/1961 Glenn 350271 X 3,145,256 8/ 1964 Holz 350271 NORTON ANSHER, Primary Examiner. RICHARD A. WINTERCORN, Assistant Examiner. 

1. ADJUSTABLE OPTICAL SLIT APPARATUS COMPRISING: A FIRST STRIP HAVING A SLIT DEFINING EDGE; MEANS CONNECTED TO SAID FIRST STRIP FOR STATIONARY MOUNTING THEREOF; A SECOND STRIP HAVING A SLIT DEFINING EDGE; MEANS COUPLING SAID STRIPS AND ADAPTED TO ALLOW LINEAR SLIDABLE MOTION OF SAID FIRST STRIP WITH RESPECT TO SAID SECOND STRIP, SAID SLIT DEFINING EDGES BEING IN ADJACENT RELATIONSHIP; MEANS CONNECTED TO SAID STRIPS YIELDINGLY BIASING SAID SECOND STRIP TOWARD SAID FIRST STRIP; A FIRST PAIR OF BLOCKS MOUNTED ONE ON EACH END OF SAID FIRST STRIP; AND A SECOND PAIR OF BLOCKS MOUNTED ON SAID SECOND STRIP EACH OPPOSITE ONE OF SAID FIRST PAIR OF BLOCKS, EACH OF SAID SECOND PAIR OF BLOCKS HAVING MOUNTED THEREON PRECISION ADJUSTMENT MEANS ADAPTED TO CONTACT THE OPPOSITE END OF SAID FIRST BLOCKS FOR PRECISION ADJUSTMENT OF THE SLIT DEFINED BY SAID EDGES. 